Features at diagnosis according to geolocation
| Europe | America | Asia | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Variable | North (>50°N) (n=1393) | South (<50°N) (n=4652) | p Value† | North (>0°) (n=881) | South (<0°) (n=253) | p Value‡ | North (>30°N) (n=640) | South (<30°N) (n=300) | p Value§ |
| Gender (female) | 1286 (92.3) | 4311 (92.7) | 0.741 | 821 (93.2) | 247 (97.6) | 0.022 | 623 (97.3) | 287 (95.7) | 0.366 |
| Age at diagnosis, years | 54±14.7 | 54±14 | 0.997 | 53.9±14.1 | 50±12.6 | <0.001 | 50.2+ 14.1 | 43.7±10.4 | <0.001 |
| Dry eye | 1251 (89.8) | 4414 (94.9) | <0.001 | 856 (97.2) | 247 (97.6) | 0.951 | 428 (66.9) | 275 (91.7) | <0.001 |
| Dry mouth | 1309 (94) | 4322 (92.9) | 0.250 | 867 (98.4) | 243 (96) | 0.057 | 496 (77.5) | 276 (92) | <0.001 |
| Abnormal ocular tests | 933/1175 (79.4) | 3519/4024 (87.5) | <0.001 | 664/780 (85.1) | 199/243 (81.9) | 0.333 | 514/608 (84.5) | 244/266 (91.7) | 0.011 |
| Schirmer’s test | 884/1171 (75.5) | 2483/2972 (83.5) | <0.001 | 499/774 (64.5) | 190/243 (78.2) | <0.001 | 452/601 (75.2) | 244/266 (91.7) | <0.001 |
| Rose bengal/other ocular dye score | 269/479 (56.2) | 1436/1703 (84.3) | <0.001 | 431/660 (65.3) | 77/97 (79.4) | 0.018 | 237/350 (67.7) | NP | NA |
| Positive minor salivary gland biopsy | 1092/1199 (91.1) | 2864/3221 (88.9) | 0.061 | 559/655 (85.3) | 176/185 (95.1) | 0.002 | 282/353 (79.9) | 244/270 (90.4) | 0.001 |
| Abnormal oral diagnostic tests | 893/1007 (88.7) | 2602/3365 (77.3) | <0.001 | 566/760 (74.5) | 205/243 (84.4) | 0.005 | 494/596 (82.9) | 3/3 (100) | 1 |
| Unstimulated whole salivary flow | 861/995 (86.5) | 1573/2382 (66) | <0.001 | 547/748 (73.1) | 185/232 (79.7) | 0.070 | 375/494 (75.9) | NP | NA |
| Parotid sialography | 41/47 (87.2) | 606/738 (82.1) | 0.572 | 29/33 (87.9) | 1/1 (100) | 1 | 10/17 (58.8) | 1/1 (100) | 1 |
| Salivary scintigraphy | 210/224 (93.8) | 1657/2019 (82.1) | <0.001 | 23/27 (85.2) | 70/80 (87.5) | 1 | 169/181 (93.4) | 2/2 (100) | 1 |
| Positive anti-Ro/La antibodies | 955/1387 (68.9) | 3470/4640 (74.8) | <0.001 | 679/880 (77.2) | 138/246 (56.1) | <0.001 | 572/633 (90.4) | 216/280 (77.1) | <0.001 |
| Anti-Ro antibodies | 946/1386 (68.3) | 3328/4637 (71.8) | 0.019 | 631/879 (71.8) | 136/246 (55.3) | <0.001 | 550/633 (86.9) | 215/280 (76.8) | 0.001 |
| Anti-La antibodies | 598/1379 (43.4) | 1974/4625 (42.7) | 0.741 | 406/880 (46.1) | 60/246 (24.4) | <0.001 | 317/628 (50.5) | 131/274 (47.8) | 0.651 |
| ANA-positive | 1020/1334 (76.5) | 3528/4259 (82.8) | <0.001 | 672/848 (79.2) | 179/248 (72.2) | 0.039 | 555/601 (92.3) | 216/284 (76.1) | <0.001 |
| RF-positive | 652/1094 (59.6) | 1931/4086 (47.3) | <0.001 | 368/834 (44.1) | 88/252 (34.9) | 0.022 | 295/595 (49.6) | 135/248 (54.4) | 0.366 |
| C3 low | 148/806 (18.4) | 546/3798 (14.4) | 0.008 | 31/728 (4.3) | 8/252 (3.2) | 0.668 | 132/601 (22) | 35/212 (16.5) | 0.201 |
| C4 low | 116/741 (15.7) | 547/3850 (14.2) | 0.416 | 78/726 (10.7) | 6/252 (2.4) | <0.001 | 60/602 (10) | 17/212 (8) | 0.651 |
| Positive cryoglobulins | 36/237 (15.2) | 262/3449 (7.6) | <0.001 | 3/42 (7.1) | 0/108 (0) | 0.048 | 2/124 (1.6) | 0/94 (0) | 0.724 |
Adjusted p values for 60 comparisons with false discovery rate correction corresponding to the comparison of European (†), American (‡) and Asian (§) countries.
In bold: statistically significant (p<0.05) variables associated with geolocation in the multivariable logistic regression analysis adjusted for ethnicity, age at diagnosis and gender.
ANA, antinuclear antibodies; NA, not available; NP, not performed; RF, rheumatoid factor.